Printers are output devices utilized to create an image on a sheet of media. One type of conventional printer 10 is shown in FIG. 1. The printer 10 may be provided with a sheet 12, a stack 14 and an input tray 16. The sheet 12 may be located on an uppermost portion of the stack 14 of media. This stack 14 may be located in the input tray 16.
The printer 10 may also be provided with a pick mechanism 18, a path 20, an imaging component 22, a fuser 24 and an output tray 26. The pick mechanism 18 may move individual sheets from the stack 14 (e.g. sheet 12) into the path 20 that extends through the printer 10. The sheet 12 travels through the printer 10 along the path 20 where a toner image may be formed on the sheet 12 by the imaging component 22. After forming the toner image on the sheet 12, the fuser 24 may fuse the toner image on the sheet 12. This fusing process creates a fused image on the sheet 12. The fused image on the sheet 12 creates a durable document that can be distributed, read, stored, etc. The output tray 26 may be located at the end of the path 20 for receiving processed sheets, such as sheet 12.
The printer 10 may be further provided with a temperature sensor 28, a controller 30 and a heater 32. The temperature sensor 28 may take the form of a thermistor located in the fuser 24. The controller 30 may be a pre-programmed application specific integrated circuit (ASIC) or pre-programmed microprocessor operationally associated with the printer 10. The heater 32 may take the form of a ceramic heater located within (or in thermal communication with) the fuser 24. In a process that will be described later herein, the heater 32 can be activated to increase the temperature of the fuser 24. The sensor 28 can report this increase of temperature to the controller 30; the controller 30 can activate or deactivate the heater 32 as required to maintain a particular temperature of the fuser 24.
The fuser 24 operates at an operating temperature xe2x80x98T1xe2x80x99 that is higher than ambient temperature xe2x80x98T0xe2x80x99. As used herein, the term xe2x80x98operating temperaturexe2x80x99T1 is defined as the temperature of the fuser 24 that allows for proper fusing of toner onto sheets of media. As used herein, the term xe2x80x98ambient temperaturexe2x80x99 T0 is defined as the temperature of the fuser 24 when the printer 10 is not being used and is essentially dormant (which results in the fuser 24 being deactivated for a long enough period of time to have any residual heat dissipated therefrom, this period of time may be about 45 minutes to one hour).
Overview of Conventional Process
The printer 10 may form and fuse the image on the sheet 12 in a series of steps as it travels along path 20 (FIG. 1). These steps may include a warm-up step, a feed step, a fusing step and an ejecting step. Timelines shown in FIGS. 2 and 3 illustrate two types of conventional forming and fusing processes. These processes are illustrated in the timelines as a time graph xe2x80x98Sxe2x80x99, a sheet velocity graph xe2x80x98Vxe2x80x99 and a fuser temperature graph xe2x80x98Txe2x80x99. The first type of conventional process illustrated in FIG. 2 is a sequential process. The second type of conventional process illustrated in FIG. 3 is a fixed delay process.
Conventional Sequential Process
With reference to FIG. 2, the sequential forming and fusing process may commence at a start point denoted by xe2x80x98Axe2x80x99. During the warm-up step occurring during period xe2x80x98S1xe2x80x99, the heater 32 (FIG. 1) may be activated to bring the fuser 24 from the ambient temperature T0 towards the operating temperature T1 (shown in the fuser temperature graph T). It takes the entire warm-up step period S1 to bring the fuser 24 to its operating temperature T1. Once the sensor 28 (FIG. 1) senses and reports the operating temperature T1, the heater 32 may be deactivated or, alternatively, power supplied thereto may be substantially reduced. By deactivating or reducing power supplied to the heater 32, the operating temperature T1 is substantially maintained. A preheated point denoted by xe2x80x98Bxe2x80x99 (FIG. 2) denotes when the fuser 24 is at the operating temperature T1. After the preheated point B, the feed step may occur during period xe2x80x98S2xe2x80x99.
Referring to FIG. 1, during the feed step period S2 (FIG. 2), the picker 18 may advance the sheet 12 from the stack 14 towards the imaging component 22 along the path 20. As shown in the velocity sheet graph V (FIG. 2), the sheet 12 may travel along path 20 at a velocity V1. The sheet 12 passes through the imaging component 22 where the toner image may be formed thereon as it travels along the path 20. At a fusing point denoted by xe2x80x98Cxe2x80x99, the fusing step may occur during period xe2x80x98S3xe2x80x99 (FIG. 2).
Referring again to FIG. 1, during the fusing step period S3 (FIG. 2), the fuser 24 may fuse the toner image to the sheet 12 as it travels along the path 20. Once the toner image is fused to the sheet 12, it has been converted to a fused image. The fuser 24 may fuse the toner image by applying heat to the toner image and sheet 12. As shown in the temperature graph T (FIG. 2), the fuser temperature may vary slightly from, but remain substantially close to, the operating temperature T1 (as previously mentioned, the operating temperature T1 may be maintained by selectively activating of the heater 32 as directed by the sensor 28 and/or the controller 30). At an ejecting point denoted by xe2x80x98Dxe2x80x99 (FIG. 2), the fusing process has ended and the ejecting step may occur during period xe2x80x98S4xe2x80x99 (FIG. 2).
During the ejecting step period S4, the sheet 12 may be ejected from the path 20. This sheet 12 is ejected to the output tray 26, FIG. 1. At an exit point denoted by xe2x80x98Exe2x80x99 (FIG. 2), the sheet 12 may be completely ejected from the path 20. After the sheet 12 is removed from the path 20, its velocity returns to zero as shown in the velocity graph V. The sheet 12 with the image formed thereon may be stored in the output tray 26 (FIG. 1) along with other sheets that have been processed.
As Illustrated in FIG. 2, the accumulation of time from the start point A to the exit point E may be referred to herein as a conventional sequential processing period denoted by xe2x80x98S5xe2x80x99. The conventional sequential processing period S5 is an accumulation of the individual steps taken to create the image on the sheet 12. As shown in FIG. 2, the conventional sequential processing period S5 may include the warm-up step period S1, the feed step period S2, the fusing step period S3 and the ejecting step period S4. The conventional processing period S5 may be calculated according to the following equation:                               S5          =                    ⁢                      S1            +            S2            +            S3            +            S4                          ,                  wherein          ⁢                      :                                                          ⁢                              S1            ⁢                          xe2x80x83                        ⁢            is            ⁢                          xe2x80x83                        ⁢            the            ⁢                          xe2x80x83                        ⁢            warm            ⁢                          -                        ⁢            up            ⁢                          xe2x80x83                        ⁢            step            ⁢                          xe2x80x83                        ⁢            period                    ;                                                ⁢                              S2            ⁢                          xe2x80x83                        ⁢            is            ⁢                          xe2x80x83                        ⁢            the            ⁢                          xe2x80x83                        ⁢            feed            ⁢                          xe2x80x83                        ⁢            step            ⁢                          xe2x80x83                        ⁢            period                    ;                                                ⁢                                            S3              ⁢                              xe2x80x83                            ⁢              is              ⁢                              xe2x80x83                            ⁢              the              ⁢                              xe2x80x83                            ⁢              fusing              ⁢                              xe2x80x83                            ⁢              step              ⁢                              xe2x80x83                            ⁢              period                        ;            and                    ,                                                ⁢                  S4          ⁢                      xe2x80x83                    ⁢          is          ⁢                      xe2x80x83                    ⁢          the          ⁢                      xe2x80x83                    ⁢          ejecting          ⁢                      xe2x80x83                    ⁢          step          ⁢                      xe2x80x83                    ⁢                      period            .                              
When a user desires to print a sheet (i.e. creating a durable image on sheet 12), this type of conventional printer 10 takes the conventional sequential processing period S5 to eject the first sheet with the image formed thereon. The conventional sequential processing period S5 to eject the first sheet is commonly referred to in the art as xe2x80x98first page out timexe2x80x99. The first page out time is a common benchmark for comparing printers.
Conventional Fixed Delay Process
Another type of conventional printer 10 that uses a fixed delay period is illustrated in a timeline in FIG. 3. This fixed delay period is denoted by xe2x80x98Sfdxe2x80x99 and is used to decrease the first page out time of printer 10. This fixed delay period Sfd may be a value that is pre-programmed into the printer at the time of manufacture. The fixed delay period Sfd is a xe2x80x98worst-case-scenarioxe2x80x99 period of time to bring the fuser 24 (FIG. 1) to the operating temperature T1. Factors that may result in the worst-case-scenario include, but are not limited to, low line voltage, low ambient temperature, high humidity, thick media, reduced resistance of the heater 32, etc.
With continued reference to FIG. 3, this forming and fusing process may commence at a start point denoted by xe2x80x98Axe2x80x99. During the warm-up step occurring during period xe2x80x98S1xe2x80x99, the heater 32 may be activated to bring the fuser 24 (FIG. 1) from the ambient temperature T0 towards the operating temperature T1 (shown in the temperature graph T.) At a preheated point denoted by xe2x80x98Bxe2x80x99, the fuser 24 is, essentially, at the operating temperature T1. After the fixed delay period Sfd, a feeding point denoted by xe2x80x98B2xe2x80x99 may represent the start of the feed step. The feed step may occur during period xe2x80x98S2xe2x80x99 that partially occurs during the warm-up step period S1. It should be noted that since the fixed delay period Sfd is determined for the worst-case-scenario, the fuser 24 is usually at the operating temperature T1 before the fusing step period S3 starts. By accommodating for the worst-case-scenario, the first page out time is slower than it could be.
With reference to FIG. 1, during the feed step period S2 (FIG. 3), the picker 18 may advance the sheet 12 from the stack 14 towards the imaging component 22 along the path 20. As shown in the sheet velocity graph V in FIG. 3, the sheet 12 may travel along path 20 at a velocity V1 towards the imaging component 22. A toner image may be formed on the sheet 12 as it travels through the imaging component 22. With referent to FIG. 3, at a fusing point denoted by xe2x80x98Cxe2x80x99, the fusing step may occur during period xe2x80x98S3xe2x80x99.
Referring again to FIG. 1, during the fusing step period S3 (FIG. 3), the fuser 24 may fuse the toner image to the sheet 12 as it travels along the path 20. Once the toner image is fused to the sheet 12, it has been converted to a fused image. The fuser 24 may fuse the toner image by applying heat to the toner image and sheet 12. As shown in the temperature graph T (FIG. 3), the fuser temperature may vary slightly from, but remain substantially close to, the operating temperature T1. At an ejecting point denoted by xe2x80x98Dxe2x80x99 (FIG. 3), the fusing process has begun and the ejecting step may occur during period xe2x80x98S4xe2x80x99 (FIG. 3).
During the ejecting step period S4, the sheet 12 may be ejected from the path 20. This sheet 12 is ejected to the output tray 26, FIG. 1. At an exit point denoted by xe2x80x98Exe2x80x99 (FIG. 3), the sheet 12 may be completely ejected from the path 20. After the sheet 12 is removed from the path 20, its velocity returns to zero as shown in the velocity graph V. The sheet 12 with the image formed thereon may be stored in the output tray 26 (FIG. 1) along with other sheets that have been processed.
As illustrated in FIG. 3, the accumulation of time from the start point A to the exit point E may be referred to herein as a conventional fixed delayed processing period denoted by xe2x80x98S7xe2x80x99. The conventional fixed delayed processing period S7 is an accumulation of time of steps taken to process the sheet 12. As shown in FIG. 3, the conventional fixed delayed processing period S7 may include the fixed delay step period Sfd, the feed step period S2, the fusing step period S3 and the ejecting step period S4. The conventional fixed delayed processing period S7 may be calculated according to the following equation:                               S7          =                    ⁢                      Sfd            +            S2            +            S3            +            S4                          ,                  wherein          ⁢                      :                                                          ⁢                              Sfd            ⁢                          xe2x80x83                        ⁢            is            ⁢                          xe2x80x83                        ⁢            the            ⁢                          xe2x80x83                        ⁢            fixed            ⁢                          xe2x80x83                        ⁢            delayed            ⁢                          xe2x80x83                        ⁢            step            ⁢                          xe2x80x83                        ⁢            period                    ;                                                ⁢                              S2            ⁢                          xe2x80x83                        ⁢            is            ⁢                          xe2x80x83                        ⁢            the            ⁢                          xe2x80x83                        ⁢            feed            ⁢                          xe2x80x83                        ⁢            step            ⁢                          xe2x80x83                        ⁢            period                    ;                                                ⁢                                            S3              ⁢                              xe2x80x83                            ⁢              is              ⁢                              xe2x80x83                            ⁢              the              ⁢                              xe2x80x83                            ⁢              fusing              ⁢                              xe2x80x83                            ⁢              step              ⁢                              xe2x80x83                            ⁢              period                        ;            and                    ,                                                ⁢                  S4          ⁢                      xe2x80x83                    ⁢          is          ⁢                      xe2x80x83                    ⁢          the          ⁢                      xe2x80x83                    ⁢          ejecting          ⁢                      xe2x80x83                    ⁢          step          ⁢                      xe2x80x83                    ⁢                      period            .                              
When a user desires to print a sheet (i.e. forming an image on sheet 12), the conventional printer 10 takes the conventional fixed delayed processing period S7 to eject the first sheet with the image formed thereon.
These conventional apparatus and methods result in the fusing point C occurring after the preheated point B By providing the preheated point B before the fusing point C, these conventional printers properly fuse the toner to the sheet 12, even if the line voltage is low, the ambient temperature is low, the humidity is high, the media is thick, the resistance of the heater 32 is reduced, etc.
In exemplary embodiments, methods and apparatus for processing a sheet may include: providing an imaging apparatus comprising an input separated from a processing component by a path, the processing component comprising an idling state and a processing state; storing a warm-up step period that is unique to the processing component, the warm-up step period being defined by a period of time to bring the processing component from the idling state to the processing stating; activating the processing component, thereby urging the processing component from the idling state towards the processing state; according to the warm-up period, moving the sheet from the input along the path towards the processing component; and processing the sheet with the processing component.